...its weird i had so manny people tell me its not going to work. but if you charge a small 12v sla, its works just fine. even works when your riding.

I wouldn't tell you that it wouldn't work, just that it's not going to do a whole lot. I doubt it's more than a 5-watt panel [edit--I'm finding panels like that which are rated at 1.2 watts]. How many watts is your motor? If you divide your motor's wattage by the panel's wattage, and that will tell you how much faster the motor can drain the battery (at full throttle) than the panel can charge it.

Of course if you don't use the e-power much, then maybe the panel would help noticeably... but then in that case,,,, the question becomes if it's really beneficial to carry around the extra weight of the solar panel at all, when it's charging a battery that's not helping move the bike most of the time anyway.

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Also I remember that someone else around here had a solar panel like that to charge the battery for their lighting setup.

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I have a dream (of after relocating to the desert-southwest US) of building a solar-powered e-trike. I figured that to run continuously on solar power alone, over level ground, at 15+ mph,,,, it would need about 600 watts of panels. A panel of that size would measure about 4 feet by 7 feet. And will cost ~$1000 for the cells, assuming one bought the cells for a DIY panel. If you paid for commercial panels it would cost even more.
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I'm sceptical that it delivers enough current for use or to significantly charge your battery.

Here's the formula if you want to check it out:

I = P/V ( rated current = Watts / Volts )

for example: a 5Watt, 12 Volt solar panel is 5/12 = .4 Amp

if your 2 amp charger takes 6 hours, your .4 amp solar panel would take you about 26 hours to charge. If you put them together, the extra .4 amps would shorten the charge time by 1.5 hours.

But I dont think you can use it on a lithium ion battery, quick charging a lithium ion only extends the amount of time needed to balance the battery pack at the end of the charge cycle. this results in a similar charge time.

It's still very cool to have, and every bit helps the range. I wouldn't mind putting a 20 watt panel on my huge trunk. It would fit on it without even overhanging. Although my range is satisfactory for me, and the $200 cost would not be worth it to save 3 cent charging. For someone who needs more range, maybe.
BTW My ID has nothing to do with Solar photovoltaics. I am into solar thermal, I have (3) solar thermal panels to heat 25% of my home in the winter.